LOW-LEVEL TRITUM MEASUREMENT WITH THE LIQUID SCINTILLATION SPECTROMETER. Progress Report No. 1

Technical Report · Thu Oct 01 04:00:00 EDT 1959

OSTI ID:4786915

Hours, R M; Kaufman, W J

The practical application of tritium to engineering problems involving water tracing is dependent on the availability of a highly sensitive yet economical method of tritium measurement. The liquid scintillation spectrometer affords a methodology for tritiated water detection at concentrations of 10-6 mu c/ml or less, and is believed to be generally superior to ion chamber or proportional type counters. Detection sensitivity was defined as the quantity of liquid that can be labeled with a unit of radioactivity and subsequently detected with a confidence level of approximately 95 per cent. Detection sensitivity may be expressed formally as a function of counter efflciency, sample volume, background, and counting time. Using a 30-min counting period, sensitivities in excess of 1800 1/ mu c were obtained wdth a scintillator comprised of dioxane, naphthalene, PPO, POPOP, and water. Scintillator volumes of over 200 ml were employed with the scintillator in direct optical contact with the photomultiplier tubes of a coincidence type spectrometer. Specifications of an insert cell for use with a commercial liquid scintillation spectrometer are given. The insert cell makes possible detection sensi-tivities of over 1000 1/ mu c. A comparison was made of the sensitivities of the single photomultiplier spectrometer and the two-photomultiplier coincidence spectrometer. It was concluded that the two systems can be operated with nearly comparable sensitivities, but for low-level measurements the latter system has the advantage of a more stable background with a lesser liability to thermionic and light-induced phosphorescence disturbances. (auth)

• Research Organization: California. Univ., Berkeley. Sanitary Engineering Research Lab; and CAlifornia. Univ., Berkeley. School of Public Health
• DOE Contract Number: AT(11-1)-34
• NSA Number: NSA-16-012959
• OSTI ID: 4786915
• Report Number(s): TID-13910
• Country of Publication: United States
• Language: English

Related Subjects

ALKANES
BACKGROUND
CHEMISTRY
COINCIDENCE METHODS
EFFICIENCY
LIQUIDS
MEASURED VALUES
NAPHTHALENE
ORGANIC NITROGEN COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PHOSPHORUS COMPOUNDS
PHOTOMULTIPLIERS
POPOP
SCINTILLATION COUNTERS
SENSITIVITY
TRACE AMOUNTS
TRITIUM
WATER